Indication repeating apparatus



Feb. 22, 1966 H. c. GRANT, JR 3,237,180

INDICATION REPEATING APPARATUS Filed March 18, 1963 2 Sheets-Sheet 1 I/' I AGENT Feb. 22, 1966 H. c. GRANT, JR

INDICATION REPEATING APPARATUS 2 Sheets-Sheet 2 Filed March 18, 1963 INVENTOR.

T N E G A mmtsom u 0 [rilll II 9 United States Patent 3,237,180 INDICATION REPEATING APPARATUS Harry C. Grant, Jr., Ridgewood, N.J., assignor to Specialties Development Corporation, Belleville, N .J a corporation of New Jersey Filed Mar. 18, 1963, Ser. No. 265,740 6 Claims. (Cl. 340-214) The present invention relates to indication repeating apparatus, and, more particularly, to such apparatus utiilzed in connection with a condition responsive system to repeat, at a remote location, the indications provided by the system.

The present invention, although useful for other purposes, is primarily concerned with apparatus to be used in conjunction with a smoke detecting system including the smoke detecting apparatus shown and described in co-pending United States application Serial No. 229,807, filed October 11, 1962, and the electrical control system shown and described in co-pending United States application Serial No. 260,007, filed February 20, 1963.

In smoke detecting apparatus of the type disclosed in the above identified co-pending application, a plurality of smoke conducting conduits or lines extending from the spaces being monitored are connected through a rotary selector valve to a smoke detecting unit. The selector valve is provided with a position indicator for continuously denoting which conduit is connected through the valve to the smoke detecting unit.

The electrical control system for such apparatus normally operates the selector valve to sequentially connect each of the conduits to the detecting unit, and, when the detecting unit responds to the presence of smoke, gives an alarm and interrupts the operation of the selector valve so that the source of the smoke may be determined from the valve position indicator. The electrical control system disclosed in the previously mentioned co-pending application, in addition to performing the above functions, also gives an indication if a fault occurs in the smoke detecting apparatus or the electrical control system.

In smoke detecting systems for use on ocean going vessels, the detecting equipment is usually located at a main station below deck and it is generally required that the indications given by the detecting equipment be repeated at a remote station, for example, in the wheelhouse of the ship so that the oflicer in charge may quickly take whatever action is required by the indications given. Therefore, it is extremely important that the indications given at the wheelhouse are accurate reproductions of those given by the detecting equipment.

The detecting equipment is frequently separated from the wheelhouse by a considerable distance; wherefore, it is highly desirable that the repeater be connected to the detecting apparatus through a minimum number of lines which are inexpensive in character and occupy a minimum of space. In previously known smoke detecting systems of this type, the remote indication of the source of detected smoke was provided by running either a smoke conducting pipe or a wire from the detecting equipment to the repeater equipment for each monitored line. Such arrangements are very costly, particularly where the system monitors a great number of spaces in which smoke is to be detected.

Accordingly, an object of the present invention is to provide indication repeating apparatus which accurately reproduces, at a remote station the indications provided by detecting apparatus at a main station.

Another object is to provide such repeating apparatus wherein the remote station is connected to the main station in a simple, convenient and inexpensive manner.

Anotoher object is to provide such repeating apparatus including an indicator which is synchronized with a line selecting device in' the .detecting apparatus to give a remote indication of the line connected to the detecting unit.

Another object is to provide such repeating apparatus including means for monitoring the synchronization of the line selecting device and such a remote indicator.

Another object is to provide such repeating apparatus including means for facilitating the re-synchronization of the line selecting device and such a remote indicator should it become necessary.

A further object is to provide such repeating apparatus which is accurate and reliable.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawings, forming a part of the specification, wherein:

FIGS. 1a and lb are schematic views of the repeating apparatus at the remote station and the detecting apparatus at the main station, respectively, including a wiring diagram for such apparatus which, when arranged with FIG. la above FIG. lb so that the terminals A through I of each view are in alignment and connected, provide a complete wiring diagram.

Referring to the drawings in detail, there is shown indication repeating apparatus in accordance with the present invention (FIG. la) utilized in conjunction with a smoke detecting system (FIG. lb).

The smoke detecting system (FIG. 1b), which is disclosed in detail in the aforementioned co-pending applications, generally comprises a photoelectric smoke detecting unit 10, an eight position rotary selector valve 11 having an outlet conduit 12 connected to the air intake of the detecting unit 10, seven input conduits or lines 13 extending from the selector valve 11 to a plurality of spaces which are to be monitored by the detecting unit, an air blower 14 connected to the air outlet of the detecting unit 10, an arrangement for step-wise rotating the selector valve including a continuously acting torque motor 15 and a stepping brake 16 mounted on a common shaft 17 with the select-or valve 11, a number wheel 18 (marked 1 to 7 and T) mounted on the shaft 17 to indicate which conduit is connected to the detecting unit 10, and a control system including control circuits schematically represented by a block 19, a brake driver schematically represented by single pole double throw switch 20, and indicating circuitry described in detail hereinafter.

The stepping brake 16 includes a disc 21 secured to the shaft 17 for rotation therewith, four armatures 22 on the disc 21 equally spaced about the circumference thereof, and two pairs of diametrically opposite braking electromagnets 24 and 25 positioned adjacent to the disc 21 to cooperate with the armatures 22 to provide a C; braking force on the shaft 17. Each magnet 24 is positioned forty-five degrees in advance of a magnet 25.

The electrical control system receives power from a transformer 26 having a primary winding 27 connected to a 115 volt alternating current line and having three secondary windings 29, 30 and 31. The secondary winding 29 provides alternating current power to the torque motor 15, the winding 30 provides power to a direct current power supply 32, and the winding 31 supplies alternating current power to a pair of conductors 34 and 35. The power supply 32 provides direct current power across a pair of conductors 36 and 37. The conductor 37 is negative and is connected directly to one side of each of the electromagnets 24 and 25. The conductor 36 is positive and is connected to the brake driver 20. The other side of the brake magnets 24 are connected to the brake driver through a conductor 38, and the other side of the brake magnets 25 are connected to the brake driver through a conductor 39.

The control system indicating circuitry includes a smoke response relay 40 and a fault relay 41 both under the control of the control circuits 19, a fault lamp 42 controlled by the fault relay 41, a smoke alarm relay 43 controlled by the smoke response relay 40, a smoke lamp 44 and a smoke gong 45 under the control of the alarm relay 43, a gong cut-off switch 46, a test switch 47 adjacent the disc 21 to be actuated by a switch operator 48 mounted on the disc 21, and a test relay 49 under the control of the switch 47.

The smoke response relay 40 includes a coil 50 connected to the control circuit 19 and a pair of normally open contacts 51. The smoke alarm relay 43 includes a coil 52 connected in series with the contacts 51 and the switch 46 between the conductors 36, 37 and also includes two pairs of normally open contacts 54 and 55. The contacts 54 are connected in series with the smoke lamp 44 between the conductors 34 and 35, and the contacts 55 are connected in series with the smoke gong 45 also between the conductors 34 and 35. The fault relay 41 includes a coil 56 connected to the control circuit unit 19 and normally open contacts, including a stationary contact 57 and a movable contract 59, connected in series with the fault lamp 42 between the conductors 34 and 35. The test relay 49 includes a coil 60 connected in series with the test switch 47 between the conductors 36 and 37 and two pairs of normally closed contacts 61 and 62 connected between the conductor 35 and the contacts 54 and 55 respectively.

A switch 63 is ganged to the switch 46 and is connected between the conductor 35 and the lamp 44 whereby the lamp 44 may be connected directly across the conductors 34 and 35.

The control circuits 19 include a timer circuit which operates the brake driver 20 to alternately connect the positive conductor 36 to the electromagnets 24 and 25, and thus alternately energize these electromagnets. The torque motor 15 constantly urges the shaft 17 to rotate, therefore, each time the brake driver changes its condition the disc 21 rotates until a pair of armatures 22 becomes aligned with the electromagnet 24 or 25 which are then energized. The selector valve 11 is thus moved in eight steps to connect each of the conduits 13 to the smoke detecting unit for a predetermined period of time during each revolution of the valve 11. The blower 14 draws air from the spaces to be monitored through the conduits 13 and the selector valve 11 into the smoke detecting unit 10 which produces an electrical signal if smoke is present. The control circuit unit 19 responds to this electrical signal and energizes the coil 50 of a smoke response relay 40 closing the contacts 51 to energize the coil 52 of the smoke alarm relay 43. The coil 52 closes the contacts 54 and 55 to energize the smoke gong 45 and the smoke lamp 44. If desired, the gong 45 may be silenced by opening the switch 46 t0 tic-energize the coil 52. By virtue of the mechanical 4 connection between the ganged switches 46 and 63, when the switch 46 is opened, the switch 63 closes to keep the lamp 44 illuminated.

During each revolution, when the selector valve 11 moves into its eighth or test position and is not connected to any of the seven sampling conduits 13, the test switch operator 48 ac-tuates the test switch 47 to operate a smoke simulating device in the detector unit 10 such as described in co-pending United States application Serial No. 212,097, filed July 24, 1962, to cause the detector unit 10 to produce an output signal. The operation of the test switch 47 also energizes the coil 60 of the test relay 49 to eifect opening of the contacts 61 and 62 to prevent the operation of the lamp 44 and the gong 45 when the smoke alarm relay 43 is energized. Furthermore, the operation of the switch 47 transmits a signal to the control circuit unit 19 to actuate circuits for supervising the operation of the detecting system. If the system is not operating properly, the coil 56 of the fault relay 41 is energized to bring the contact 59 against the contact 57 and thereby effect illumination of the fault lamp 42.

The indication repeating apparatus according to the present invention (FIG. 1a), which is utilized in conjunction with the detecting system just described, generally comprises a remote valve position indicator including a continuously acting torque motor 64, an eight position stepping brake 65, and a number wheel 66 (marked 1 to 7 and T) all mounted on a common shaft 67; circuitry to monitor the synchronization of the number wheel 66 with the valve 11 and to re-synchronize them when an out of synchronization condition is indicated; remote smoke and fault indicating circuitry; and power failure indicating circuitry as will be described hereinafter.

The stepping brake includes a disc 69 secured to the shaft 67 for rotation therewith, four brake engaging members 70 carried by the disc and equally spaced about the circumference thereof, and a pair of brake solenoids 71 and 72 positioned adjacent the circumference of the disc 69 and provided with armatures 74 and 75 respectively which are extended to be engaged by one of the members 70 to stop the disc 69 when the solenoids 71 and 72 are energized. One side of the solenoid 71 is connected through. a conductor 76 to the conductor 38 leading from the brake driver 20, and one side of the solenoid 72 is similarly connected through a conductor 77 to the conductor 39. The other sides of the solenoids 71 and 72 are both connected through a conductor 79 to the negative conductor 37. The solenoid 74 is therefore energized when the brake magnet 24 is energized, and the solenoid 75 is energized at the same time as the brake magnet 25 is energized. In this manner, when the detecting apparatus and the repeating apparatus are in synchronism, the numbers wheels 18 and 66 give the same indication.

The synchronization circuitry includes a synchronization test switch 80 adjacent the disc 69, a synchronization fault relay 81 and lamp 82 in the repeater, a synchronization fault relay 84 and lamp 85, a re-synchronization switch 86 in the repeater, two synchronization switches 87 and 89, an additional pair of normally closed contacts. 90 in the test relay 49, and an additional stationary contact 91 in the fault relay 41 normally in contact with the: movable contact 59. As shown herein, the relay 84,. lamp 85, switches 87 and 89, and contacts 90 and 91 are in the circuitry at the main station (FIG. lb).

The test switch 80 is positioned adjacent the circumference of the disc 69 to be actuated by a switch operator 92 on the disc 69 each time the number wheel 66 indicates that the valve 11 is in the test position.

The repeater synchronism fault relay 81 includes a coil 94, a pair of normally open contacts 95, and a pair of normally closed contacts 96. The synchronism fault relay 84 (FIG. 1b) includes a coil 97 and a pair of normally open contacts 98. One side of the coil 94 is connected to the conductor 79. The other side of the coil 94 is connected through a conductor 99, the switch 87, and a conductor 100 to the conductor 38. The conductor 100 is also connected through the contact 90 to the conductor 39. One side of the normally open contacts 95 is connected to the conductor 35 through a conductor 181 and the other side is connected through the lamp 82 and a conductor 102 to the conductor 34. The normally closed contacts 96 are connected between the conductor 102 and a conductor 104 leading to one side of the coil 97 of the relay 84. The other side of the coil 97 is connected to the conductor 34 through the contacts 91 and 59 of the relay 41.

The torque motor 64 is connected across the winding 29 through the switch 86 and a conductor 105 on one side and through a conductor 106 and the switch 89 on the other side.

The operation of the synchronizing circuitry will now be explained. The repeater torque motor 64 constantly urges the shaft 67 to rotate. The solenoids 71 and 72 are alternately energized by the action of the brake driver to stop the rotation of the shaft 67. Each time the brake driver 20 changes its condition, the solenoid holding the disc 69 from rotating is released and the other solenoid is energized, therefore, the disc rotates one eighth of a revolution. In this manner, the number wheel 66 is stepped through eight positions during each revolution. Since the solenoids 71 and 72 respectively are energized at the same time that the brake magnets 24 and 25 are energized, the number wheel 66 will keep in step with the selector valve 11 and give the same indications at the main and remote stations.

When the conductor 38 is energized by the brake driver 20, the relay coil 94 receives current from the conductor 38 directly through the conductor 100, and, when the conductor 39 is energized, the relay coil 94 receives current from the conductor 39 through the contacts 90 of the test relay 49. In this manner, the relay 81 is held energized as the selector valve 11 moves through the positions indicated as 1 through 7 on the number wheel 18. When the selector valve 11 moves into the test position T the conductor 39 is energized to actuate the brake magnets 25, and the test switch 47 is closed by the operator 48 to energize the test relay coil 60 and open the contacts 90. The current flow through the switch 87 to the relay coil 94 is thus interrupted. If the number wheel 66 is synchronized with the selector valve 11, the operator 92 will close the switch 80 at the same time that the switch 47 is closed. Current will then flow from the conductor 39 through the conductor 77 and the switch 80 to the coil 94 and the relay 81 will remain energized. If the number wheel 66 is not synchronized with the selector valve 11, the switch 80 will not be closed at this time and the relay 81 will drop out closing the contacts 95 to light the lamp 82 and opening the contacts 96 to de-energize the relay 84 and light the lamp 85.

If the repeater valve position indicator is out of synchronization with the valve 11, re-synchronization may be accomplished from either the main station or the repeater station by the following procedures.

Re-synchronization may be accomplished from the repeater station by opening the switch 86 when the number wheel 66 is in number 1 position, and holding the switch 86 open until the lamp 82 lights and goes out again. Opening of the switch 86 stops the motor 64 and holds the number wheel 66 in the number 1 position. When the valve 11 moves to the test position T the lamp 82 is illuminated as described hereinbefore. The lamp 82 is extinguished when the valve 11 moves to the next position in which it connects line number 1 to the detector 10. Therefore, when the lamp 82 goes out, the number wheels 66 and 18 are both indicating line number 1. The switch 86 is closed while the valve 11 is in this position to re-start the motor 64 so that the number wheel 66 remains synchronized with the number wheel 18.

Re-synchronization from the main station may be accomplished by opening switch 87 to de-energize the relay 81 which is turn de-energizes the relay 84 and lights the lamp 85, holding the switch 87 open at least until the operator 92 closes the switch (when the number wheel 18 is in the test position T) and reenergizes the relays 81 and 84 to extinguish the lamp 85, opening switch 89 when the lamp goes out to de-energize the motor 64 and hold the number wheel 66 in the test position T, holding the switch 89 open until the number wheel 18 indicates that the valve 11 is in the test position T, and closing the switches 87 and 89 to re-connect the relay 81 and re-energize the motor 64.

The remote smoke and fault indicating circuitry comprises a fault relay 189, including a coil 110 and a pair of contacts 111, a fault lamp 112, a smoke lamp 114, a smoke gong 115, a gong cut-off switch 116, a switch 117 ganged to the switch 116, and an additional pair of contacts 118 in the alarm relay 43.

The coil 110 of the fault relay 109 is connected between the sync fault lamp 82 and the conductor 102. The contacts 111 of the faul relay 109 are connected in series between the conductors 102 and 101. The smoke gong 115 is connected between the conductors 79 and 102, and the smoke lamp 114 is connected between the conductors and 102. In order that the smoke gongs 45 and 115 may both be turned off from either the main station or the repeater station, the negative side of the coil 52 of the alarm relay 43 is connected through the switch 46, a conductor 119 leading to the repeater, and the switch 116 to the conductor 79. The switch 117 is connected between the conductors 101 and 105 to provide current to the lamp 114 when the switchest 116 and 117 are operated. The contacts 118 are connected between the contacts 61 of the test relay 49 and the conductor 79 to provide A.C. to the repeater gong 115.

The operation of the remote smoke and fault indicating circuitry will now be explained.

When the control circuit unit 19 energizes the smoke response relay 50, current flows from the positive conductor 36 through the contacts 51 of the relay 50, the coil 52 of the alarm relay 43, the contacts 46, and the conductor 119 to the repeater, through the switch 116 to the conductor 79, through the conductor 79 back to the negative conductor 37 in the main station. In response to the current flow through the coil 52, the contacts 54, 55, and 118 close. As previously described, the contacts 55 connect the main station gong 45 across the conductors 34 and 35, and the contacts 54 connect the lamp 44 across the conductors 34 and 35. The closing of the contacts 54 also provides a current path from the conductor 35 through the contacts 61 and 54, the conductor 105, the repeater smoke lamp 114, and the conductor 102 to the conductor 34. The closing of the contacts 118 provides a current path from the conductor 35 through the conductor 79, the repeater smoke gong 115, and the conductor 102 to the conductor 34.

If, after a smoke alarm is given, it is desired to silence the gongs 45 and 115 this can be accomplished by operating the ganged switches 46 and 63 in the main station or the ganged switches 116 and 117 in the repeater. Operation of either switch 46 or 116 interrupts the current flow through the coils 52 of the relay 43 causing the contacts 54, 55, and 118 to open and de-energize the gongs 45 and 115 and the lamps 44 and 114. The concurrent operation of the switch 63 or 117 re-connects the lamps 44 and 114 across the conductors 34 and 35 to maintain a fire indication.

When the control circuit unit 19 energizes the fault relay 41 in response to a mulfunction in the smoke detecting system, the movable contact 59 is moved from the contact 91 to the contact 57. The fault lamp 42 is thus connected across the conductors 34 and 35, and the current flow between the conductors 34 and 35 through the coil 97 of the relay 84, and the coil of the fault relay 109,

is interrupted. The fault relay 109 is thus de-energized thereby closing the contacts 111 to connect the fault lamp 112 between the conductors 34 and 35. Although the synchronism fault relay 84 is also re-energized at this time, the lamp 85 ist not illuminated since the operation of the fault relay 41 disconnects the contact 91 from the conductor 35.

The power failure indicating circuitry includes a relay 120 having a coil 121 and a pair of contacts 122, a bat tery 124, and a lamp 125. The coil 121 is connected between conductors 101 and 102 and the contacts 122 are connected in series with the battery 124, and a lamp 125. The coil 121 is normally energized and maintains the contacts 122 open. In the event of a power failure, the power supplied to the conductors 101 and 102 from the conductors 34 and 35 disappears and the coil 121 is de-energized. The contacts 122 then close to connect the lamp 125 across the battery 124 to give a power failure indication.

The indication repeating aparatus described herein requires only ten conductors 76, '77, 99, 101, 102, 104 to 106, and 119 extending between the main station and the repeater station. While the apparatus has been described in connection with a smoke detecting system having an eight position valve for monitoring seven smoke lines 13, it will be understood that such apparatus can be utilized in connection with a valve having a greater number of positions divisable by four, for example, up to forty-eight, without requiring any additional conductors between the main and repeater stations or additional components other than the required number of brake members 22 and 70 for stepping the number wheels 18 and 66 correspondingly to the number of positions.

From the foregoing, it will be seen that the present invention provides simple, inexpensive and reliable indication repeating apparatus which is connected to main station detecting apparatus in a simple and inexpensive manner and which accurately reproduces the indications provided by the detecting apparatus.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

1. In apparatus of the class described the combination of main station equipment including condition responsive indicating means, a plurality of condition transmitting lines, a multiposition selecting device having a plurality of positions each for connecting a separate one of said lines to said indicating means and having a test position, and means for moving said selecting device through its various positions; remote station equipment for monitoring the position of said selecting device including a second device for correspondingly following the positions of said selecting device to at all times indicate the position of said selecting device, and means for moving said second device at the same rate as said first mentioned device; first switch means associated with said selecting device to be operated only when said selecting device is in its test position; second switch means associated with said second device to be operated only when said second device is in test position; and means responsive to said first and second switch means for giving a fault indication when said second switch is not operated when said selecting device is in said test position.

2. Apparatus according to claim 1, wherein said main station equipment also includes a power source, a plurality of conductors for delivering power to said means for moving said selecting device and said means for moving said second device, and switch means for alternately connecting said conductors to said power source, and said fault indication means including an indicator, a first relay for actuating said indicator connected to said conductors to be held in energized condition, and a second relay having a control circuit connected to said first switch and having a controlled circuit providing the connection between said first relay and one of said conductors, said second switch being connected in parallel with said controlled circuit.

3. Apparatus according to claim 2, including a first synchronizing switch at the repeater station and a second synchronizing switch at the main station both for inerting said means for moving said second device, and a third synchronizing switch at the main station for interrupting the current flow through said controlled circuit.

4. Apparatus according to claim 3, wherein said means for moving said selecting device includes a motor for driving said selecting device, a second power source connected to said first motor, and an electrically operative brake connected to each of said conductors to be alternately energized to cause said selecting device to be moved in steps, said means for moving said second device includes a second motor for driving said second device, said second motor being connected to said second power source, and an electrically operative brake connected to each of said conductors to be alternately energized to cause said second device to be moved in steps, said first and second synchronizing switches being connected between said second motor and said second power source.

5. In apparatus of the class described the combination of main station equipment including condition responsive indicating means, a plurality of condition transmitting lines, a multiposition selecting device having a plurality of positions each for connecting a separate one of said lines to said indicating means and having a test position, first indicating means for indicating the positions of said selecting device, means for moving said selecting device and said first indicating means through its various positions, and means for controlling the operation of said moving means; remote station equipment including second position indicating means for correspondingly indicating the positions of said selecting device, and means under the control of said controlling means for moving said second position indicating means at the same rate as said selecting device; first switch means associated with said main station equipment to be operated only when said selecting device is in its test position; second switch means associated with said remote station equipment to be operated only when said second indicating means indicates that said selecting device is in its test position; and means responsive to said first and second switch means for giving a fault indication when said second switch is not operated when said selecting device is in said test position.

6. In apparatus of the class described, the combination of main station equipment including a multiposition selecting device, a first motor for driving said selecting device, first stepping brake means including at least two brake members adapted to be alternately energized for stopping said device in each of its positions, a first power source for said brakes having alternately energized outputs and a common output, a second power source for said first motor, a third power source having first and second terminals, condition responsive means, first and second switch means under the control of said condition responsive means; remote station equipment including means for indicating the positions of said selecting device, a second motor for driving said position indicating means, second stepping brake means including at least two brake members adapted to be alternately energized for stopping said position indicating means when said device stops, and first and second condition indicators; and means interconnecting said main station equipment and said remote station equipment including first and second conductors extending from said second motor to said second power means, a third conductor connected between each of said first and second condition indicators and said first terminal of said third power source, a plurality of conductors connecting said stepping brake members of said second stepping brake means to said outputs of said first power 9 10 source including a common conductor connected between References Cited by the Examiner each of said brake members and said common outputcf UNITED STATES PATENTS said first power means, said first condition indicator being connected between said common conductor and said third 2,351,014 6/1944 Connery al conductor, said second condition indicator being connected 5 2,695,399 11/ 1954 Martin 340214 between said first conductor and said third conductor, said 2,695, 00 11/ 1954 Snitjer 340213-1 first switch means being connected between said common 2,798,214 7/ 1957 Rowell 340-214 conductor and said second terminal of said third source, 2,870,254 1/1959 Slayton et a1 178-69 and said second switch means being connected between 2,985,869 5/1961 A smith 340 213.1

said first conductor and said second terminal of said third 10 source. NEIL C. READ, Primary Examiner. 

5. IN APPARATUS OF THE CLASS DESCRIBED THE COMBINATION OF MAIN STATION EQUIPMENT INCLUDING CONDITION RESPONSIVE INDICATING MEANS, A PLURALITY OF CONDITION TRANSMITTING LINES, A MULTIPOSITION SELECTING DEVICE HAVING A PLURALITY OF POSITIONS EACH FOR CONNECTING A SEPARATE ONE OF SAID LINES TO SAID INDICATING MEANS AND HAVING A TEST POSITION, FIRST INDICATING MEANS FOR INDICATING THE POSITIONS OF SAID SELECTING DEVICE, MEANS FOR MOVING SAID SELECTING DEVICE AND SAID FIRST INDICATING MEANS THROUGH ITS VARIOUS POSITIONS, AND MEANS FOR CONTROLLING THE OPERATION OF SAID MOVING MEANS; REMOTE STATION EQUIPMENT INCLUDING SECOND POSITION INDICATING MEANS FOR CORRESPONDINGLY INDICATING THE POSITIONS OF SAID SELECTING DEVICE, AND MEANS UNDER THE CONTROL OF SAID CONTROLLING MEANS FOR MOVING SAID SECOND POSITION INDICATING MEANS AT THE SAME RATE AS SAID SELECTING DEVICE; FIRST SWITCH MEANS ASSOCIATED WITH SAID MAIN STATION EQUIPMENT TO BE OPERATED ONLY WHEN SAID SELECTING DEVICE IS IN ITS TEST POSITION; SECOND SWITCH MEANS ASSOCIATED WITH SAID REMOTE STATION EQUIPMENT TO BE OPERATED ONLY WHEN SAID SECOND INDICATING MEANS INDICATES THAT SAID SELECTING DEVICE IS IN ITS TEST POSITION; AND MEANS RESPONSIVE TO SAID FIRST AND SECOND SWITCH MEANS FOR GIVING A FAULT INDICATION WHEN SAID SECOND SWITCH IS NOT OPERATED WHEN SAID SELECTING DEVICE IS IN SAID TEST POSITION. 